Azo compounds (azos) are widely used as radical initiators in the polymerization industry. Nonetheless, due to the azo group molecular structure, azos gravitate toward thermal decomposition and lead to thermal runaway accidents. In this paper, the thermal decomposition behaviors of 2-(1-cyano-1-methylethyl)azocarboxamide (CABN) under the dynamic and adiabatic environments were investigated using differential scanning calorimetry and accelerating rate calorimeter. Several safety assessment parameters such as time to maximum rate under adiabatic condition (TMRad), temperature of no return, and self-accelerating decomposition (SADT) temperature were calculated based on thermokinetic analysis as well as curve fitting. The results indicated that CABN decomposes at low temperatures (90.0–100.0 °C) and releases huge volumes of gaseous products, which may set off a fire, deflagration, or even explosion if the decomposition occurs uncontrolled in a confined space. Compared with commonly used azos, the shorter TMRad, lower SADT, and more heat from thermal decomposition reflect the potential thermal explosion hazards of CABN. To investigate emergency response procedure in terms of industrial applications, the oxygen-balance method was further used to evaluate the explosion hazard of CABN, and several recommendations on alleviating the thermal hazards of CABN were established to prevent catastrophic accidents.
Yi-ming Lu, Shanghao Liu, C. Shu
Journal of Thermal Analysis and Calorimetry